DE69632848T2 - One-piece light band with light-emitting diodes - Google Patents

Abstract

An integral single piece extruded LED light strip and an associated process for producing such an LED light strip. The light strip includes first and second bus elements spaced apart from one another by a predetermined distance. The light strip also includes at least one light emitting diode (LED) connected between the bus elements that is illuminated when the first bus element conducts electricity provided from a power source. An extruded plastic material completely encapsulates the first and second bus elements and the LED, thereby providing a barrier to protect the elements from damage and to make the light strip impervious to moisture. A process for manufacturing an integrally formed single piece light strip includes the steps of continuously feeding bus elements to an extruder; continuously feeding circuitry having at least one LED operatively mounted thereon to the extruder; and extruding a thermoplastic material at a temperature below that which would damage the circuitry or the LED to thereby encapsulate the bus elements, the circuitry and the LED and to operatively connect the circuitry to the bus elements.

Description

Background of the Invention

The The invention relates generally to light strips and in particular to one massive light strip, which is formed in one piece and light-emitting diodes contains and a method for producing such a light strip, in which the diodes and the associated Circuits against moisture penetration and other possible causes of damage protected are.

Luminous strips with light-emitting diodes (LED) are commonly used to provide visible paths or marked locations in otherwise dark, unlit areas. Such LED light strips are advantageous compared to light bulb or lamp markings because the strips are relatively inexpensive to manufacture and are very easy to attach. In addition, the LEDs used in these light strips generally have a longer lifespan than conventional lamps or light bulbs. Examples of these conventional designs include W092 14092 (Consumerville Ltd) and US A4173035 (Hoyt Steven D). Another example of such conventional designs is US 4761720 which discloses all the features of the preamble of claim 1.

modern LED light strips consist of circuits that have numerous LEDs included that are mounted on a substrate and attached to electrical conductors are connected. The circuit is of a tubular and partially transparent protective sheathing is included connected to a power supply in order to illuminate the LEDs in a targeted manner bring to. Two exemplary designs for LED strips are general in U.S. 5,130,909 (Gross) on July 14, 1992 entitled "Emergency Lighting Strip ", and in U.S. 4,597,033 (Meggs et al.), published June 24, 1986 entitled "Flexible Elongated Lighting System ", described. Such strips are in numerous arrangements for the Use in buildings and used outdoors, for example as markings for escape routes, Markings for exit doors and lighting arrangements for decoration.

Independent of In the application it is imperative that the LED circuit be connected to any protected Sheathing is surrounded. The protective covering must be sufficient be firm so damage be avoided at the circuit by heavy loads, e.g. B. the Weight of equipment that acts directly on the strip. Since the LED circuit for damage and malfunctions, by wetness arise, very vulnerable the protective jacket must also be impermeable to moisture.

The LED light strips protect the circuits incorporated in them, but are subject to inherent Restrictions. The tubular coats, which is usually used as a housing for current LED light strips are used, offer little protection against mechanical damage of the LED circuits due to excessive loads, the on the coats act. In addition, the aforementioned light strips offer the LED circuits only a limited one Protection against moisture. The jacket seals or strip ends, through which introduced the LED circuits are usually vulnerable for the Penetration of moisture. In addition there are protective coats like those mentioned Patents are built up, essentially hollow, and thus increase the vulnerability such coats for moisture condensation. This makes such light strips from the point of view of moisture protection frequently unreliable, especially in outdoor lighting applications or in other applications where the strips are extreme weather conditions are exposed. Consequently, it is desirable to use the LED circuits to be surrounded with a more durable protective sheath, which the mentioned Disadvantages of tubular coats does not have.

A Kind of permanent protective sheath is commonly used for encapsulation used by electroluminescent lamps (EL). The protective coat will by sealing a multilayer EL lamp assembly through a conventional Foil or hard lamination process. In this conventional Hard lamination process becomes an upper protective film layer either by gluing or thermal melting with a lower layer a protective film through the use of high Temperatures and high pressure rollers, the EL lamps between the Layers are included. An example of this conventional one Type is GB2284305, which has all the features of the preamble of claim 9 disclosed.

Although the EL strips produced with the above hard lamination process offer a protective jacket, the multilayer EL lamps accommodated in such strips are nevertheless exposed to moisture damage. Moisture can often penetrate into the interior of the two-piece strip through the fused or bonded seal that connects the two-piece sheath, particularly when the strips are used outdoors or when the two-piece jacket's bonded joint is aged the strip is weakened. In addition, such a hard lamination process for use in LED circuits would not be desirable. EL lamps contain multiple layers of conductive and non-conductive material that is essentially flat and easily interposed between egg embedding an upper and a lower lamination layer. In contrast, since the LEDs in LED light strips typically have a height of 1.016 mm (0.040 inches) or more, the high pressure rollers typically used to connect or melt the two-piece housing could crush the projecting LEDs when forming an LED strip. In addition, the high temperatures encountered in the joining or melting steps in a hard lamination process would expose the LEDs and associated circuitry to heat destruction, rendering an LED strip made with such a process inoperable.

Therefore there is a need for an improved solid LED light strip out of one piece, the impermeable to moisture and a high level of protection against other potentially harmful Offers influences. There is also a need for a soft lamination process for making a long solid LED light strip from one Piece, in which a protective jacket encapsulates the LED circuits so that a massive LED light strip is inexpensively made from one piece without that the circuits are damaging high pressures or exposed to high temperatures.

Summary of the invention

According to a first aspect of the invention, a solid light strip is provided which is formed in one piece, comprising:
first and second bus elements which are at a predetermined distance from one another,
at least one light strip circuit held on a flexible substrate, which is electrically connected to the first and second bus elements and contains at least two light emitting diodes (LEDs) which are connected in series, the LEDs lighting up when the light strip circuit conducts electricity, and
a semi-rigid plastic material provided on the outside, which completely encloses the first and second bus elements and the or each light strip circuit, so that a uniform, seamless, essentially gap-free protective cover is formed,
characterized in that the semi-rigid plastic material is injection molded around the first and second bus elements and the or each strip light circuit, and in that the LEDs of the or each strip light circuit on the strip light are spaced apart in the longitudinal direction.

Prefers contains the light strip also has at least one resistance between the bus elements are connected in series with the LEDs. The light strip may further comprise a first number of LEDs that are between the bus elements are switched, and contain a substrate strip on which numerous discrete printed circuits are located. The LEDs are mounted on the discrete printed circuits so that the Luminous strips can be cut into individual sections, the discrete printed circuits. The substrate strip comprises preferably a substrate strip made of polyester, fiberglass or polyimide.

On third bus element can be electrically connected to the light strip circuit be provided, at least one resistor being functionally between the third bus element and the second bus element connected in parallel and at least one LED is connected in series with the resistor is. The molded plastic material can be an ionomer resin include high density polyethylene or a polychlorotrifluoroethylene.

To the strip can also be an elongated one channel-like guidance belong, which picks up the light strip.

According to a second aspect of the invention, there is provided a method for producing a solid luminous strip in one piece, comprising the steps:
the continuous feeding of bus elements to an overmolding machine,
the continuous supply of luminous elements to the extrusion machine,
the injection molding of a plastic material at a temperature which is below a temperature which would damage the lighting elements in order to enclose the bus elements and the lighting elements,
characterized in that the luminous elements contain light-emitting diodes (LEDs) which are contained in numerous strip light circuits, with at least two LEDs being functionally attached to each strip light circuit, which are connected in series and have a longitudinal spacing from one another along the strip light.

The The method can also include the step of performing the included bus elements and Light strip circuits between shaping rolls include the shape the light strip.

The invention relates to a solid injection molded LED light strip, which has first and second bus elements which are at a predetermined distance from one another and which are functionally connected to a power supply so that they conduct electricity. Furthermore, at least two light-emitting diodes (LED) are connected between the bus elements, which light up if the bus elements conduct electricity that is supplied by the power supply. An injection molded soft laminate plastic material material completely encloses the first and the second bus element and the LED and brings about a functional contact between the first and second bus element and the LED. The molded plastic material also provides a barrier that protects the components from damage and makes the light strip impervious to moisture.

The The invention also relates to a soft lamination process for manufacturing a solidly designed light strip in one piece. The The process includes the steps: continuous feeding Bus elements to a spraying machine; continuous feeding of Circuits on which at least one LED is functionally mounted is to the spraying machine; and injection molding a thermoplastic Plastic at a temperature that is below a temperature the damages on the circuits would cause so that the bus elements and the circuits are included and the circuits are functionally connected to the bus elements become.

The Advantages and features mentioned and various other advantages and features of the invention will appear from the following description and the claims in conjunction with the accompanying drawings out.

Brief description of the drawings

It shows:

1 a perspective view of a light strip of a preferred embodiment of the invention;

2 a perspective view, partially in cross section and broken, of the encapsulated in the plastic material LED circuits;

3 a cross-sectional view of the in 1 pictured strip mounted in a protective channel;

4 a sketch of a method for producing the LED light strip of the invention;

5 a second embodiment of the invention;

6 a third embodiment of the invention;

7 a fourth embodiment of the invention;

8th a top view of the implementation of numerous individual segments of an LED strip light of the in 1 illustrated way of illuminating a portion of an airport runway; and

9A - 9B Top views of further arrangements of LEDs implemented in the LED light strip of the invention.

Detailed description of the preferred embodiments

Reference is now made to the drawings. An LED light strip according to the preferred embodiment of the invention is in 1 shown generally at 10. The light strip contains LED circuits, which are shown generally at 12 and are described in more detail below. They are in a solid thermoplastic housing 14 encapsulated from a piece that has no internal cavities. This is the glow strip 10 not only durable and able to withstand considerable loads, but also impervious to moisture. So that are the LED circuits 12 protected against damage caused by penetrating moisture. The thermoplastic housing 14 is preferably constructed of a polymer material having a low vapor transmission rate, for example, Surlyn ^®, an ionomer resin, a high density polyethylene, or polychlorotrifluoroethylene.

2 shows the light strip in 1 , the housing being partially cut along section line 2-2 to expose the encapsulated LED circuitry. The LED circuits 12 , please refer 2 , are on a substrate 16 mounted, which contains a printed circuit. The substrate is preferably a polyester film that is approximately 0.127 mm (0.005 inches) thick. However, any substrate can be used, for example fiberglass or a polyimide substrate, which has the parameters which are required for the manufacturing process described below. The printed circuit contains conductive bus contacts 20a . 20b , which run lengthways along the strip and are functional with the conductor tracks 22 connected to the printed circuit. A resistance 24 ( 1 ) and light emitting diodes (LEDs) 26 Known design are functional on the PCB traces 22 between the conductive bus contacts 20a . 20b connected. The bus contacts 20a . 20b of the printed circuits make electrical contact with the bus elements 30a respectively. 30b forth, which also extend in the longitudinal direction over the strip. It is described in more detail below that the bus elements 30a . 30b are connected to an external power supply. This is about the bus elements 30a . 30b from an external power supply specifically supplied electricity so the LEDs 26 depending on certain predetermined conditions that are associated with the particular application of the light strip. In 1 are three LEDs 26 on the substrate 16 shown assembled. At this point it should be clarified that you can in a similar way can implement any number of LEDs.

3 shows a cross-sectional view of the light strip in 1 , In accordance with the preferred embodiment of the invention, the light strip is approximately 10.2 mm (0.4 inches) high and 33.0 mm (1.3 inches) wide. If it is necessary for a special application, the LED light strip, see 3 , even in a protective channel 34 mounted, which is made of aluminum or a high-density plastic. The strip is pulled into the aluminum channel from one side and then permanently attached to the channel with a known connecting means. After forming a flat gutter in concrete, asphalt or a similar surface using a known cutting tool, the channel can 34 and the light strip recorded therein is inserted into the channel and installed flush with the finished surface without the surface being adversely affected. The channel 34 offers the light strip additional protection against heavy loads that act on the light strip and also simplifies the flush mounting of the light strip in certain areas, such as airport runways or highways. Such a system of light strips and channels could have light strips with lamps of different colors, which are switched on or flash alternately by a central control, for example an airport control tower, as required. It is also contemplated that such a system could be designed to meet the relevant sections of the FAA Circular AC15015345-64A.

4 shows a double-injection production line for producing an LED strip light according to a preferred embodiment of the invention. As shown, a continuous path of an LED strip substrate is shown 40 including the resistors and LEDs that are functionally mounted on a printed circuit of the substrate from an LED strip light 42 fed. Although it is shown that a continuous path of an LED strip substrate from the roll 42 is supplied, of course, individual sections of the light strip substrate individually from the roll 42 or a similar feed mechanism. A first continuous path of a first bus element 44 is from a first bus element role 46 fed. In the same way, a second continuous path of a second bus element 50 from a second bus element role 52 fed. The bus elements 44 . 50 just like the light strip substrate could be supplied in individual sections and not in continuous tracks. The bus elements can be fed in such a way that the elements are arranged above or below the conductive bus contacts of the substrate, as desired. The continuous paths of the LED circuits mounted on the substrate 40 and the bus elements 44 and 50 are made by feed rollers 54a and 54b united. They are then fed into a molten thermoplastic stream that is produced by the injection molding machines 60a and 60b is supplied in the form of an upper layer and a lower layer. The thermoplastic material is injected at a temperature of less than 177 ° C (350 ° F), ie the temperature at which the LEDs are thermally destroyed and the polyester substrate ripples. The injection temperature can, however, change depending on the particular thermoplastic material used and the particular process parameters.

After the spraying machines 60a and 60b Once the circuits and bus elements have been encapsulated in one piece in the housing, the top and bottom layers of the molded thermoplastic material are individually molded in molding rolls 62a . 62b provided with a profile after the nozzle has emerged 56 at a temperature of approximately 171 ° C (340 ° F). Note that the distance between the nozzle and the forming rolls 62a . 62b covered, can be changed for different degrees of cooling of the newly formed strip depending on the particular mass of the sprayed strip.

you note that through this profiling both the top layer as well as the bottom layer of the sprayed material can. This allows control of the displacement of the sprayed material after insertion of the LED circuits mounted on the substrate into the injection molding machine. Therefore, excess spray material can be used Removed and removed with a strip cutter (not shown).

After exiting the nozzle and passing through the forming rolls 62a . 62b the newly formed LED strip lights up 63 into a cooling tank 64 , The cooling tank preferably contains chilled water into which the newly formed strip is made 63 is immersed for a predetermined period of time. After this predetermined period of time, the LED light strip turns on 63 from the cooling tank 64 through conveyor rollers 70a . 70b a cutting machine 72 known type supplied and cut into individual sections with a predetermined length. The light strip can be cut into individual segments in accordance with the individual printed circuits on the polyester substrate to which the LEDs are electrically connected. The injected thermoplastic material thus envelops the LED circuits mounted on the substrate and the bus elements in a one-piece housing. Since each individual LED in the strip arrangement is enclosed in the thermoplastic material that forms the housing, the LEDs are against one another isolated. Since the LED light strip is cut to a desired length between any discrete printed circuits formed on the polyester substrate, no LED arrays are exposed.

5 shows another embodiment of the invention, generally with 110 is designated. With the light strip 110 comprises a substrate 112 conductive bus contacts 114 . 116 . 120 that are electrical with the bus elements 124 . 126 . 128 are connected. The bus elements 124 and 126 and the associated conductive bus contact tracks 114 and 116 are arranged adjacent to each other. The contact strip is located here 120 and the associated bus element 128 far right in the strip 110 , The printed conductor track 130 is between the bus contact 114 and the bus contact 120 connected. The printed conductor track 140 is between the bus contact 116 and the bus contact 120 connected. A resistance 132 and the LEDs 134a - 134c are electrical with the printed conductor 130 connected. A resistance 142 and the LEDs 144a - 144c are electrical with the printed conductor 140 connected. To prevent the printed trace 130 electrically with the bus contact 116 comes into contact, there is a non-conductive surface 150 between the bus element 126 and the printed conductor 130 so the track 130 has no electrical contact to the bus element.

6 shows the electrical connection of two LED strips 210 and 212 , As shown, includes a first end of the light strip 210 an electrical connector 214a , and a second end contains an electrical connector 214b , Similarly, the light strip contains 212 a first end that is an electrical connector 216a has to the connector 214b the light strip 210 fits. The second end of the light strip 212 has an electrical connector 216 , which is used to connect to another light strip or to a terminating element (not shown). The connector shown 214a fits an electrical connection 220 an external power supply 222 that supplies the light strip with electrical energy. The electrical connectors 214a . 214b and 216a . 216b are, as shown, metallic connecting pins which are melted into the thermoplastic and which make contact with the bus elements of the strip so that the light strips can be connected or the light strips to the power supply 222 can connect. Matching pins in the strips can be made with wires 224 . 226 connect and then in a protective cover 230 lock in. The electrical connectors can also be constructed as the connector disclosed in US Patent 5,391,088, assigned to AMP Inc., entitled "Surface Mount Coupling Connector", which is hereby incorporated by reference. One could alternatively strip the sheathing that encloses the bus elements from the bus elements and connect the bus elements to one another or connect them to an external power supply using conventional wiring methods.

7 shows another preferred embodiment of the invention, generally at 300 is shown. The light strip contains a substrate 316 , which runs as a printed circuit bus contacts 320a . 320b contains the electrical contact to the bus elements 330a . 330b manufacture, and PCB traces 322 between the bus contacts 320a . 320b are switched. A resistance 342 and LEDs 344a . 344b are on the PCB traces 322 assembled. They are brought to light when the bus elements 330a . 330b Conduct electricity that is supplied by an external power supply. The LED light strip 300 however also contains a microcontroller 352 known design. The microcontroller 352 enables the strip to be addressed 300 , whereby the LED circuits contained in the LED light strips can be pulsed or made to light up in a specific pattern so that a specific passage is clearly marked.

8th shows an envisaged environment in which the numerous light strips 10 of the invention can be implemented. In this special environment, individual sections of the light strips are inserted into protective, flush-mounted channels, for example the channel 34 , and electrically connected to each other with said means so that they are a waiting place for a jet plane 50 form. It is thought that an implementation of these light strips for aircraft waiting areas or the lighting of the current runway would mark these paths more clearly than the currently used and significantly more expensive implemented lighting systems. In addition, the LED light strip of the invention represents a significant improvement over conventional airport lighting systems, such as the MR-16 halogen light system, since the LED light strips can be attached to the runway surface and only slightly disturb the runway surface integrity. For the light strip of the invention, it is no longer necessary to bury cables, as they belong to conventional runway lighting systems. Since the LED light strips are mounted on the surface, additional difficulties are avoided, for example problems that often occur in connection with the groundwater level.

It is also contemplated that the LED light strips of the invention can be made with any number of desired rows or arrangements of encapsulated LEDs can manufacture and implement. 9A and 9B show two such alternative arrangements. The at 400 in 9A LED light strip shown contains a number of LEDs, which are generally at 442 are shown. You are on a PCB trace 422 arranged and form an X. The at 500 in 9B The illustrated LED light strip includes numerous LEDs, which at 542 are shown. You are on a PCB trace 522 arranged and form an arrow or a zigzag pattern. Strips like her at 400 and 500 could be used together with a microcontroller, for example the microcontroller 352 in 7 to display a STOP or FREE signal depending on the situation on a specific runway or other traffic situation.

you note that with the procedure described, any Number of bus wires and that you can have any number of rows or arrangements LED circuits mounted on the substrate electrically with the bus elements can connect.

you also note that the LED light strip of the invention is for penetrating Moisture completely impermeable and can therefore be used in certain underwater applications, for example aquarium or swimming pool lighting. The stake this LED light strip could Savings versus usual Effect lighting systems.

you note that with the procedure described, the LED light strips can be formed with numerous cross-sectional shapes, for example rectangular, curved, elliptical or with any other desired Shape. This is done in a known manner by modifying the Forming rolls in the thermoplastic injection molding machine.

The The description above represents the preferred embodiment of the invention. Of course the invention can be modified without changing the scope or leaves the meaning of the appended claims. Professionals can do different things recognize further advantages of the invention after having the present Studied text and the drawings along with the following claims to have.

Claims (10)

Solid light strip ( 10 ) which is formed in one piece, comprising: first ( 30a ) and second ( 30b ) Bus elements which are at a predetermined distance from one another, at least one light strip circuit ( 12 ) that are electrically connected to the first and second bus elements ( 30a . 30b ) is connected and at least two light emitting diodes (LEDs) ( 26 ) which are connected in series, the LEDs lighting up when the strip light circuit ( 12 ) Conducts electricity, and a semi-rigid plastic material provided on the outside ( 14 ) that the first ( 30a ) and second ( 30b ) Bus elements and the or each strip light circuit ( 12 ) completely encloses, so that a uniform, seamless, essentially gap-free protective cover is formed, characterized in that the at least one light strip circuit ( 12 ) from an elastic substrate ( 16 ) and that the semi-rigid plastic material around the first ( 30a ) and second ( 30b ) Bus elements and the or each strip light circuit ( 12 ) is sprayed around and that the LEDs ( 26 ) the or each strip light circuit ( 12 ) on the light strip ( 10 ) are spaced from each other in the longitudinal direction. Light strips ( 10 ) according to claim 1, characterized in that the light strip also has at least one resistor ( 24 ) which is between the first ( 30a ) and second ( 30b ) Bus elements to the LEDs ( 26 ) is connected in series. Light strips ( 10 ) according to claim 1 or 2, characterized in that the light strip ( 10 ) also a first number of LEDs ( 26 ), which between the first bus element ( 30a ) and the second bus element ( 30b ) are switched. Light strips ( 10 ) according to claim 3, characterized in that the light strip ( 10 ) also a substrate strip ( 112 ) containing numerous discrete printed circuits ( 130 ) with the LEDs ( 130a - c ) on the discrete printed circuits ( 130 ) are mounted so that the light strip ( 10 ) can be cut into individual sections that correspond to the discrete printed circuits ( 130 ) correspond. Light strips ( 10 ) according to claim 4, characterized in that the substrate strip ( 112 ) comprises a substrate strip made of polyester, fiberglass or polyimide. Light strips ( 10 ) according to any one of the preceding claims, characterized in that the light strip also comprises a third bus element ( 128 ) which is electrically connected to the strip light circuit ( 12 ) connected is; that at least one resistance ( 142 ) functionally between the third bus element ( 128 ) and the second bus element ( 126 ) is connected in parallel; and that at least one LED ( 144a - c ) to the at least one resistor ( 142 ) is connected in series. Light strips ( 10 ) after any of the before claims, characterized in that the molded plastic material contains an ionomer resin, a high density polyethylene or a polychlorotrifluoroethylene. Light strips ( 10 ) according to any preceding claim, characterized in that the light strip also contains an elongated channel-like path which receives the light strip. Process for the production of a massive light strip ( 10 ) in one piece, comprising the steps: the continuous feeding of bus elements ( 30a . 30b ) to an extrusion machine, the continuous supply of luminous elements ( 26 ) to the extrusion machine, the injection of a plastic material ( 14 ) at a temperature that is below a temperature that the illuminants ( 26 ) would damage the bus elements ( 30a . 30b ) and the filament ( 26 ) are included, characterized in that the luminous elements ( 26 ) Contain light emitting diodes (LEDs), which are used in numerous light strip circuits ( 12 ) contained by an elastic substrate ( 16 ) are worn, whereby on each strip light circuit ( 12 ) at least two LEDs ( 26 ) are functionally attached, connected in series and along the light strip ( 10 ) are spaced from each other in the longitudinal direction. The method of claim 9, further comprising the step of performing the included bus elements ( 30a . 30b ) and strip light circuits ( 12 ) between shaping rollers that hold the light strip ( 10 ) to form.